The present invention relates to a new electronic key and cylinder system and method and, more particularly, to a system and method which can be employed with standard mortise locks and cylinder locks. An electronic key which incorporates electronics and IR devices for communicating with lock electronics for authorization and access to actuate the lock are provided in a moisture impervious housing on the key.
A major problem which results in thefts is that doors are left unlocked, and unauthorized duplicates and copies of duplicates of master keys are in the hands of many people which allows quick entry to and access from rooms and buildings. The degree of key control is limited by the type of cylinders and keys used. Any new keying system must include key control. Sophisticated lock cylinders are believed to have advantages because they cannot be readily compromised by the use of standard key blanks available to any professional locksmith or even a hardware store.
Solutions to date have included products with an interchangeable core or conventional cylinders with restricted keyways, mechanical high-security lock cylinders and electronically reprogrammable access control system using keys or cards. The latter have been used in connection, for example, with electronic products such as radar warning devices to limit access to the rightful owner. Cincinnati Microwave offers such a "Digital Key" feature in connection with its "ESCORT" and "SOLO"-brand radar detectors.
Electronic key locks are generally known as shown in U.S. Pat. No. 3,688,269, in which a key blade has an array of holes and non-holes, with each row of holes representing a coded word. The key is inserted into a key reader, and if the proper key is inserted, an ACCEPT output will be produced at a terminal which can be used to operate a lock mechanism. Such a key cannot be reprogrammed and has the disadvantage of its digital code being at the exposed blade which is subject to damage, bending or the like. Furthermore, although the number of available digital codes is substantial, nevertheless the number is not as high as desirable to reduce the possibility of duplicating the key by an unauthorized user.
U.S. Pat. No. 4,298,792 discloses another type of a digitally coded data carrier in the form of a key which carries the data on a non-mechanical coded track. A lock contains sensors which interact with the coded track without contact to generate an output signal which is fed to a memory that contains the correct information for unlocking the system, thereby providing different code permutations which are several orders of magnitude higher than lock and tumbler systems. The coded track is intended to be invisible to the human eye and transparent to infrared radiation. A disadvantage of such an arrangement, however, is that the key cannot be reprogrammed remotely to provide a new access code.
Key devices which incorporate an electronic circuit for use with a vehicle mechanical lock are known as shown in U.S. Pat. No. 4,922,736. The knob or rear portion which contains the circuit comprises two halves made of a synthetic resin material and joined together with a bonding agent, a snap engagement or the like. Light emitting diodes are provided on both sides of the key blade. A power source is provided on one side of the circuit board located in the knob portion, as well as a push button switch which is necessary to activate the code transmission circuit. Separate contacts for electrically connecting the circuit of the key with the vehicle engine control circuit are provided on each side of the key. The manufacture of this key is made more expensive and complicated by the need to produce two knob halves and then join them together with a sufficient seal. In this connection, the protection of the electronic circuit from the harmful effects of moisture cannot be positively assured due to the interface along the entire periphery of the knob. Due to the contact design at the sides of the key blade, a special key design is required which precludes the use of this device with standard door and cabinet locks. The requirement to have two separate contacts also makes the design unnecessarily complicated and expensive to produce. In addition, the system with which this key is used requires battery cells and a push-button switch within the knob itself which must be pressed which the key itself is being turned in order to obtain a coded light signal from the LEDs in the knob.
Another type of coded key is shown in U.S. Pat. No. 4,593,185 which uses a standard door key or card on which a layer is burned by a laser beam to code with fine, discrete depressions which are subsequently read by a unit which contains the correct coding information and decides if the user is authorized to gain access. Although this is a relatively simple approach, the coding of the key is fixed and this does not provide the flexibility achieved with codings which can be changed. Thus, new keys must be produced and provided each time the coding of a lock is changed. Moreover, the coded portions of the key are at the exposed key blade where the fine depressions are subject to wear and damage which may prevent actuation of the lock if the memory unit cannot read the code.
Another type of electronic locking system having a reprogrammable key is described in U.S. Pat. No. 4,789,859 for use with a mortise lock. Electronic logic circuitry is provided with the mortise lock cylinder to recognize the full insertion of the key and extract encoded information from the key memory located in the exposed key blade. The logic circuitry in the cylinder can alter the codes in the key memory based on data transmitted from the cylinder, and can alter codes stored in the cylinder based upon data from the key memory. A key centering and retention device can be provided in the cylinder to interact with a notch on the key to ensure the proper location of the key within the keyway.
A security door system which incorporates electronics in the knob of a dimpled "smart key" for operating a deadbolt is offered under the "KABA NOVA" trademark of Lori Corporation. It is designed to install quickly on conventional doors without hardwiring in order to minimize installation costs and materials. Lost keys can be invalidated quickly without the costs of cutting and distributing new keys. The keys can be reprogrammed indefinitely with the need for cutting each time system designs or authorizations are changed and can be used not only as an electronic key, but also as a mechanical key. The electronic intelligence can be programmed to limit access by location and even by time window. A time/calendar module decides when to open or remain locked. A programming unit is designed to determine not only who is allowed to open a certain door, but also to find out who most recently did. A problem with this approach, however, is that the leads to the electronic circuit inside the knob are exposed and can very easily be damaged. In addition, the knob is comprised of two halves which must be joined together and sealed to prevent moisture intrusion and damage to the electronic circuit.
Various other types of coded keys are known, for example, U.S. Pat. No. 4,663,952 shows a key having a microprocessor in a recess in the key handle connected with an opto-electronic component for photo-electric transmission for signal currents and a miniature shell core half for output currents. U.S. Pat. No. 4,726,205 shows a vehicle ignition key which has transmitter electronics in a two-part handle which is Joined by dovetail guides. These and similar arrangements have substantial disadvantages in the key construction and in the flexibility of the key-lock system.
An object of the present invention is to provide a simple yet effective intelligent key-lock system which is usable in a variety of locks and further avoids the need to replace standard lock components.
Another object of the present invention is to utilize a method for producing a key which is less expensive than conventional key assembly methods and yet produces a superior key which is moisture-proof.
A further object of the present invention is to produce a key with the minimum number of components to reduce costs and, at the same time, provide a key configuration which allows usage as both an electronic key and a mechanical key.
A still further object of the present invention is to provide an electronic key whose sensitive components are completely covered by a plastic housing to prevent damage thereto.
Yet another object of the present invention is the provision of an electronic cylinder which is easily assembled with substantially snap fittings to minimize the need for more expensive operations, such as soldering, and which allows the use of plastic parts in the cylinder.
A still further object of the present invention is the ability to use the intelligent key lock system in a standard, mechanical lock in which the cylinder accommodates the necessary parts so as to avoid the need to dismantle an existing mechanical lock.
Another object of the present invention is to allow the use of an external power source in a simple manner to power the system in the event of failure of the system power source.
The foregoing and other objects have been achieved in accordance with the present invention by the use of a system in which the key is powered externally from a lock mechanism through a metallic/insulator layer layout of the key blade when the key is inserted in the lock mechanism. Communications between control circuitry within the key itself and the circuitry within the lock are carried out by respective IR diode and optical detector units in the key and lock. The lock mechanism on, for example, a door contains a battery, a microprocessor and associated memory, and an external communication port for effecting communications with a remote supervisory terminal/storage facility. Precursor verification codes are necessary before the lock mechanism (e.g., a solenoid) will respond to key insertion.
The key of the present invention consists of a blade, a knob portion on which a PCB is laid, and a one-piece molded plastic housing surrounding the PCB in a moisture-proof manner. The blade acts as one of the contacts, and a positive contact separated from the blade by an insulator seat extends from the PCB through the housing along a portion of the key blade. The key can be configured to be used only as an electronic key or as both an electronic and mechanical key. The positive contact can be flush with the surface of the key blade or raised therefrom so as to require a keyway with a matching profile and thereby provide a "mechanical polarization" which permits insertion of the key in only one orientation. The molded housing surrounding the PCB also serves to Join and secure the positive contact and insulator seat to the blade. The housing also can be provided with a notched portion for allowing the use of an external power unit in the event the system power supply fails, e.g., a battery.
The method of molding the housing in one-piece avoids the need for and expense of two separate housing parts and also the manufacturing process of sealing the two halves together. The plastic injection molding method of the present invention utilizes a two-part mold which defines the housing configuration and a slide which locates two IR devices in their precise desired location relative to the key blade and protects those devices during the molding operation by creating a cavity around the devices which can subsequently be filled with a protective coating or IR sensitive plastic lenses.
The cylinder according to one embodiment of the present invention includes leaf-spring contact arms which are snap-fitted into a plastic housing. The contact arms for the positive and negative contact have the same configuration, but, when a flush positive contact key is used, a rider pin can be inserted in the contact arm associated with the positive contact to prevent that contact arm from coming into contact with the key blade until the positive contact is aligned with the contact portion of that contact arm and the rider pin is dropped into a blind hole on the key blade. The IR devices and leads can also be snap-fitted into the housing to minimize the need for soldering connections to the contact arms and the IR devices. A low-battery warning light can also be provided in the cylinders to alert the system user to imminent failure of the system power supply.
According to another embodiment of the present invention used in a standard mechanical lock, an electronic cylinder can replace the innards of the mechanical lock without requiring the lock to be dismantled. To this end, the electronic cylinder portion which is inserted in the standard cylinder body comprises a solenoid housing, fixed and moving contacts, wiring, pin assembly, channel for the wiring, a spring loaded cam locator, a moving keyway cylinder, and the IR devices as one complete assembly in which the key must be inserted to rotate the keyway cylinder and can only be withdrawn from that cylinder in a particular orientation, e.g., a vertical position of the key.
Where compactness is particularly desired, the lock electronics can be located in the lock rose instead of in a separate enclosure attached to the inside of the door.